package main

import (
	"fmt"
	"io/ioutil"
	"os"
	"strings"
)

func main()  {
	counts := make(map[string]int)
	for _,filename := range os.Args[1:]{
		data,err := ioutil.ReadFile(filename)
		if err != nil{
			fmt.Fprintf(os.Stderr,"dup3:%v\n",err)
			continue
		}
		for _,line := range strings.Split(string(data),"\n")  {
			counts[line]++
		}
	}

	for line,n := range counts  {
		if n > 1 {
			fmt.Printf("%d\t%s\n",n,line)
		}
	}

}
